Ashok Leyland has launched the BS IV range of trucks and buses with Intelligent Exhaust Gas Recirculation, i-EGR. recently. Ashok Leyland has been working differently from the industry in the past, and ensures all its development were unique to India and meets local market, Customer and application requirements. Inline mechanical fuel pumps for BS III emission norms was the start of this and inline engine portfolio was one big factor that helped to increase the market share of Ashok Leyland.

Similarly development of single step front engine full flat floor bus, Jan bus was something unheard earlier and Ashok Leyland’s “Innovative Indian Engineering” made it  possible and the product is now ready for Left hand driven markets as well. Inline with that Ashok Leyland has gone with i-EGR for achieving BS IV emission norms.


While the world is revolving around conventional EGR system for BS IV, Ashok Leyland has taken a step forward in overcoming some of the issues in the EGR and offering system called i-EGR. In a nut shell, both are using a common platform of achieving the emission norms by recirculating the exhaust gas.

These gases goes back to the engine cylinders deprives certain amount of oxygen and further leads to lower temperature burn. The similarity ends here and let us see the difference below:

1.Combustion Chamber efficiency  

The whole intelligence lies in improving the combustion efficiency by working on In-cylinder combustion management. Ashok Leyland has reworked on the combustion chamber and related design to achieve the required emission level.

2.Removal of POC

The traditional EGR has EGR valve, EGR cooler to cool the exhaust gas, Diesel Oxidation Catalyst (DOC), Particle Oxidation Catalyst (POC). Now coming to the i-EGR, POC is now completely removed and hence problem of POC choking with soot is eliminated. Ashok Leyland has claimed that  the efficiency in the combustion chamber is still maintained without POC.

3. % of Exhaust gas recirculated

Now coming to the core of recirculating exhaust gas, there is a strategy behind the percentage of exhaust gas that is to be re-circulated. Ashok Leyland is following a strategy of recirculating 10% to 11% of exhaust gas. Also the opening of EGR valve follows a particular strategy.

4. Reduced electronics

Ashok Leyland has reduced electronics in the engine with limited no of sensors. This makes the system lesser complex.

5. Increased Pay load

Since the Urea tank and related accessories are now removed, there is an increase in payload which is attributed to the reduction in Un Laden Weight ULW.

6. Overall lesser TCO

Since there is no additional cost involved in adding Ad-blue or Urea solution which costs arounf Rs.70/litre and with same or increase in fuel performance, Ashok Leyland claims overall lesser “Total cost of Ownership”

High level mathematics like nonlinear partial differential equations involved in achieving the required emission norms and with 200 engineers, Ashok Leyland has worked on this for more than 4 years to achieve this upto  400hp of engine power. Currently both ‘H’ series engines and ‘N’ Series Neptune engines are available in same technology.

Ashok Leyland has claimed following advantages for its i-EGR based BS IV vehicles

  1. Maximum common parts between BS III and BS IV engines.
  2. Same oil change interval between BS III and BS IV engines.
  3. Lower injection pressure compared to EGR and hence better engine life.
  4. Upto 10% better fuel performance, than equivalent BS III vehicles for select applications.

It’s to be noted that, Ashok Leyland own’s one of the largest company that develops and manufactures products for exhaust after treatment such as SCR, diesel particulate filter and combined systems, Albonair. This company which operates from Germany, India and China supplies SCR systems to Volvo and many other global OEM’s. And Ashok Leyland has sold Albonair based BS IV SCR buses since 2010.When the same was raised as a question to Dr. Seshu Bhagavathula, Chief Technology Officer, Ashok Leyland, he opined “We have developed a simpler system which is cost effective and offers at par emission levels with SCR. So cost wise we are cheaper and we have not claimed that our technology is superior than SCR”. He also added some of the issues our Customers faced with SCR is now overcome with i-EGRa. Its to be noted that Ashok Leyland still has SCR based systems for certain applications and may offer both the technology depending on the product application.

Going forward we will follow field reports and performance of the system in long run. As of now the vehicles are matching fuel performance to BS III level and we will update with more details as and when time travels.


By CV News

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